Abstract Introduction Multiple studies have demonstrated Rezum therapy to effectively alleviate lower urinary tract symptoms secondary to benign prostatic hyperplasia while preserving sexual function. However, long-term real-world outcomes on sexual function are lacking in patients with baseline erectile dysfunction (ED) following Rezum treatment. Objective To compare four-year sexual function outcomes after Rezum between patients with and without baseline ED. Methods A retrospective study was conducted on patients from a multiethnic population treated with Rezum between 2017-2019. Patients were stratified into one of two cohorts based on presence or absence of ED at baseline. Sexual function was assessed with the validated 15-question International Index of Erectile Function (IIEF) questionnaire. Those who completed the IIEF questionnaire at baseline and 6-, 12-, and/or 48-months postoperatively were included. Function domains were calculated based on IIEF guidelines on clinical application of the questionnaire, and included erectile function, orgasmic function, sexual desire, intercourse satisfaction, and overall satisfaction. Results Ninety-one patients were included: 44% (40) with baseline ED and 56% (51) without baseline ED. At baseline, 50% of the ED cohort were taking ED medications. No significant differences were found in age, prostate volume, and past medical history of hypertension or dyslipidemia between the cohorts. The ED cohort had a significantly greater proportion of patients with diabetes mellitus when compared to non-ED cohort (35 vs 15.7%, p=0.048). At baseline, the ED cohort had significantly lower scores for the IIEF domains of erectile function (p=0.007), orgasmic function (p=0.034), intercourse satisfaction (p=0.033), and overall satisfaction (p=0.002) when compared to the no ED cohort. Between the cohorts, no significant differences in the number of injections utilized during treatment in the lateral or medial prostatic lobes were observed. Compared to baseline, there was no significance in any IIEF domains in either cohort at 6-months. At 12-months, the ED cohort had significant percent decreases in orgasmic function (-25%, p=0.018), sexual desire (-22.2%, p=0.039), and overall satisfaction (-33.3%, p=0.004), while the non-ED cohort had a significant percent increase in erectile function (5%, p=0.04) when compared to baseline. At 48-months, the non-ED cohort had no significant changes in any IIEF domains, while the ED cohort had significant percent increases in erectile function (30%, p=0.013), sexual desire (22.5%, p=0.023), intercourse satisfaction (20%, p=0.011), and overall satisfaction (58.3%, p=0.008). At 48-months, there were no cases of de novo ED in the non-ED cohort and no significant changes in ED medications in the ED cohort when compared to baseline (53.3 vs 46.7%, p=0.72). Conclusions At long-term, Rezum preserved sexual function in patients with no baseline ED and improved sexual function in patients with baseline ED. However, patients with baseline ED may experience temporary decreases in sexual function at 12-months postoperatively. Additional larger studies are warranted to further evaluate these real-world results. Disclosure No.